I'm again i think that we can use the browser search engine removing this 2: ddg", "ebay-it".
So can use this one:
"lij": {
"default": {
"visibleDefaultEngines": [
"google", "bing", "amazon-it", "paroledigenova-lij", "wikipedia-lij"
]
}

I looked into creating the icon as per documentation we have, and it's more complicated that I thought it would be. I may just add all the other search engines in the meantime, because this is taking too long.
I'll poke in more to the icon work, and will let you know.